Torsion bar spring draft sensing means for implement hitch mechanism



March 8, 1966 K. E. HANSSMANN 3,239,013

TORSION BAR SPRING DRAFT SENSING MEANS FOR IMPLEMENT HITCH MECHANISMOriginal Filed Dec. 19, 1960 4 Sheets-Sheet l JZ Izzy Z0 15 f0 Z6 7 52'5 mum (P Z6 2; ZZ

.411 ORA/5 March 1966 K. E. HANSSMANN TORSION BAR SPRING DRAFT SENSINGMEANS FOR IMPLEMENT HITCH MECHANISM 19, 1960 4 Sheets-Sheet 2 OriginalFiled Dec.

70 flu A my a H x ,L w/

Z 1 M M y m x m u m a v A l a? mm A w W a VM March 8, 1966 K. E.HANSSMANN 3,239,013

TORSION BAR SPRING DRAFT SENSING MEANS FOR IMPLEMENT HITCH MECHANISMOriginal Filed Dec. 19, 1960 4 Sheets-Sheet 5 ArToEA/Eg K. E. HANSSMANNTORSION BAR SPRING DRAFT SENSING MEANS FOR March 8, 1966 IMPLEMENT HITCHMECHANISM 19, 1960 4 Sheets-Sheet 4 Original Filed Dec.

55 8;? 64 1/11 vex/roe United States Patent 3,239,013 TORSION BAR SPRINGDRAFT SENSING MEANS FOR IMPLEMENT HITCH MECHANISM Kurt E. Hanssmann,Naperville, Ill., assignor to International Harvester Company, Chicago,Ill., a corporation of New Jersey Original application Dec. 19, 1960,Ser. No. 76,903. Divided and this application May 23, 1963, Ser. No.287,732

12 Claims. (Cl. 17210) This application is a division of the applicationSerial No. 76,903, filed December 19, 1960, for Torsion Bar Spring DraftSensing Means for Implement Hitch Mechanism.

This invention relates to implement-attaching hitch mechanisms foragricultural tractors and is particularly concerned with the draftcontrol system usually employed therewith. More specifically, however,it is directed to improvements in the type of control system in whichthe draft load is balanced against a force-resisting and yieldablemeans, generally in the form of a spring, and a power lift mechanism isactuable responsive to variations in the draft load for adjusting theworking depth of an attached implement in consonance with suchvariations.

Heretofore, means have been provided for the balancingof draft load ordraft forces in such systems and most frequently this was accomplishedby the use of some form of spring, or springs, operative to resist thecompression and tension forces produced in the draft links of the hitchlinkage mechanism used for connecting the implement to the tractor. Inthe structure disclosed in the Martin Patent 2,440,550 a pair ofside-by-side coiled springs were connected to the upper link, and in theChambers Patent 2,437,875 a single coiled spring associated with theupper link was interconnected for two-way reaction therewith, while inthe Du Shane Patent 2,940,530 a transversely disposed deflecting bar wasused as the resiliently yieldable means for balancing the draft forcesin the hitch linkage. These prior devices while generally acceptable forthe purpose were not entirely satisfactory because they either were notsufliciently sensitive, foolproof, or adequately responsive to changesin draft loads, or, in some instances, were too costly to fabricate,while in other instances, they could not be adapted for incorporation ina conventional tractor without effecting substantial and costlystructural changes therein.

The present invention, therefore, has for its principal object theprovision of an implement draft control system that overcomes theaforementioned disadvantages and handicaps of prior systems.

Another object is to provide an improved and simplified resilientlyyieldable means that occupies a minimum amount of space for balancingdraft forces and for transmitting sensing signals indicative of theresultant forces to power lift actuating means for adjusting the workingdepth of an attached implement attendant the variations in draft loadson said implement.

A further object is to provide force resisting and yieldable means inthe form of members stressable in torsion that are interconnectedbetween the draft means and the tractor for resisting compression andtension forces produced in said draft means as a result of variations indraft loads on an attached implement, and wherein the angular icemovement of certain of these members is employed to initiate a sensingsignal for effecting actuation of the power lift valve or actuator meansaccording to the draft loads on the implement,

A still further object is to provide means interconnecting a draft linkof a hitch mechanism to a tractor, and wherein said interconnectingmeans is disposed transverse to the direction of movement of said draftlink and is reactive in torsional stressing to resist compression andtension forces produced in said draft link as a result of variations indraft loads imposed on an implement attached by said hitch mechanism tothe tractor.

A more general object is to provide a highly sensitive, readilyresponsive and inexpensive to fabricate force-resisting and yieldablemeans employing therewith a member stressable in torsion which ispositively interconnected between a draft link of a hitch mechanism andan associated tractor vehicle, and wherein longitudinal movements ofsaid draft link attendant variations of draft loads imposed on anattached implement are transmitted with fidelity and without lost motionor time lag to the actuating valve means of an associated power liftmechanism.

The foregoing and other objects and advantages are attained by thepresent invention, various novel features of which will be apparent fromthe description herein and the accompanying drawings disclosing severalembodiments of the invention and will be more particularly pointed outin the appended claims.

FIGURE 1 is a fragmentary side-elevational view of the rear portion of atractor and an attached implement wherein the proposed invention hasbeen incorporated in association with the upper link of a hitchmechanism;

FIGURE 2 is a schematic view, partly in section, showing the power liftmeans, its valve actuator, and the proposed sensing and control meanstherefor;

FIGURE 3 is a fragmentary vertical sectional view, in enlarged detail,taken generally along the line 3-3 of FIGURE 1;

FIGURE 4 is a fragmentary side-elevational view, in enlarged detail,showing the upper link mounting mechanism, of FIGURE 3;

FIGURE 5 is a view similar to FIGURE 1 but showing an application of theinvention as applied in association with the lower draft links of thehitch mechanism;

FIGURE 6 is a fragmentary side-elevational view, in enlarged detail,showing the lower link mounting mechanism of the form of the inventionshown in FIGURE 15;

FIGURE 7 is a fragmentary vertical sectional view taken generally alongthe line 7-7 of FIGURE 6; and

FIGURE 8 is a schematic view similar to FIGURE 2 but showing the valvedevice and its associated components, conditioned for raising theattached implement.

Referring now to the drawings, it will be seen that the arrangementselected for depicting one preferred form or application of theinvention includes a tractor vehicle having a frame indicated in itsentirety by the reference numeral 10 and having at the rear portionthereof a rear housing assembly 11 which supports in conventionalfashion laterally spaced traction wheels such as the Wheel shown at 12.

The tractor has associated therewith the power-lift unit means showndiagrammatically in FIGURES 2 and 8 and indicated generally by thereference character 13, and this unit may be mounted in a secondaryhousing such as 14,

carried by the tractor frame lit and may include a rockshaft journaledtherein. A cylinder 16 fashioned within said housing has a piston 17therein joined by a connecting rod 18 to a crank arm 19 constrained forrotation with said rockshaft, and a pair of laterally spaced lift arms,only one of which is shown at 29, are mounted on opposite ends of saidrock shaft and are suitably secured thereto for rotation therewith. Eachof said lift arms 20 is connected by a drop link 21 (only one of whichis shown) to a lower draft link 22 which latter link, in turn, ispivotally connected for vertical and swingable movement at its forwardend, as indicated at 23, to the rear portion of the tractor and at itsrearward end, as indicated at 24, to the frame 25 of the attachedimplement represented herein as a plow 26. The rigid mast portion 27 ofsaid implement has the upper end thereof pivotally connected at 28 to anupper or top draft link 29 which, in turn, is connected at its forwardend to the tractor. The lower links 22, 22 and the upper link 29comprise what are commonly termed implement-attaching linkage mechanismor draft means for effecting a draft connection between the tractor andthe implement being borne by the Vehicle.

The hitch mounting means constituting the support for the forward end ofthe upper link 29 on the tractor incorporates therein theforce-resisting and yieldable means which represents one preferred formof the present invention and will next be described.

A load-spreading and reaction force orienting support or mountingassembly indicated generally at 30 includes a vertically disposed bodyportion 31 provided with apertures 32 through which bolts 33 may bepositioned for securely afiixing said assembly to a rear vertical faceof the rear axle housing assembly portion of the tractor frame 10.Projecting rearwardly from the body 31 and laterally spaced-apartthereon are a pair of journalling lugs or blocks 34, 34. Saidjournalling blocks have transversely disposed aligned apertures 35, 35therein, and journaled within said apertures in bearing sleeves 35a is atranversely extending sleeve or hollow tubular member 36. One end ofsaid sleeve or tube has suitably affixed thereto, by any well known orconventional means, a collar or end plate member such as 37 having anopening 38 therein for receivably positioning one end of an elongatedtorsion rod member 39. The opening 38, as shown, is generally square incross-section and is dimensioned and shaped to receive in closelyfitting relation a similarly conformed enlarged or upset end portion 40on the torsion rod 39. It will be appreciated, of course, that splineson said rod end 49 with matching splines in the aperture 38 could beprovided, or that other geometric conformations for the rod end and itscomplemental opening, could just as well be used, in lieu of the squaredrod and hole connection illustrated for mounting said rod within thecollar 37 so as to prevent relative rotation therebetween, withoutdeviating from any of the teachings of this invention. The opposite endof said torsion rod is also provided with an enlarged or upset endportion such as 41 which may be similarly conformed and then slidablyreceived in a complemental opening 42 fashioned in the hub 42a of aninsert or bushing-like member 42b which, in turn, is positioned in acircular opening 42c in a wall-like arm or anchor bracket 43 extendingrearwardly from the body portion 31 of said mounting assembly. Thebushing 42b may include a radially extending flange 43a which hasprovided therein an axially and radially extending slotted opening 43band a circumferentially and radially extending slotted opening 430. Alocking capscrew 44a extends through the circumferentially slottedopening 43c and is threadably received in a threaded aperture 44b in theanchor bracket 43. An eccentric cam screw 440 is positioned in theradially slotted opening 431) and is threadably received in a threadedaperture 44d in said anchor bracket. With this mounting means for thetorsion bar, it will be appreciated that rotational adjustment thereofmay readily be made in order to effect a small rotational displacementof the rod without disturbing the associated components of the mechanismas will subsequently be better understood.

Affixed to the sleeve or tubular member 36 are a pair of laterallyspaced-apart link connecting arms 44, 44 which are constrained forrotation with said sleeve, and said arms are provided with axiallyaligned openings 45, 45 therein adapted to receive a pin, such as 46,having a spherical portion 47 thereon for accommodating a matingspherical aperture 48 in the forward end of the top or upper link member29. Diametrically opposite t-he arms 44, 44 and mounted on the sleeve 36for rotation therewith are another pair of laterally spacedapart controlrod connecting arms 49, 4-9 having aligned slot-like or irregular-shapedapertures 50, 5'0 therein adapted to receive a pin 51 with a sphericalportion 52 thereon for positioning in a mating spherical aperture 53 inthe rearward end of a sensing control or push rod 54. As shown, the arms44, 44 and 49, 49 are connected by welding to the sleeve 36 but it willbe appreciated that any well known means, such as splining or otherwise,may be used, if preferred, for afiixing the arms to the sleeve withoutdeviating from any of the essential teachings hereof. It will also beappreciated that the arms 44, 44 and 49, 49 together with a portion ofthe interconnecting sleeve 36 may be spoken of as a bell-crank orreaction lever means.

As thus arranged, it will be evident that when a force is applied by wayof the link 29 to the link connecting arms 44, 44 such force, in turn,is transmitted by way of the interconnected push-rod arms 49, 49 to thesensing push-rod 54 for transmitting a sensing signal to the actuatorvalve unit as will subsequently be described. It will be apparent, ofcourse, that any force applied to the arms 44, 44, by way of link 29,tends to rotate the sleeve 36 within its journal blocks 34, 34 and whenthis occurs the sleeve carries with it the attached torsion rod 39.Since the opposite end of said torsion rod is anchored against rotationby means of the insert bushing 42b and anchor bracket 43, said bar willthereupon tend to twist along its length and, in doing so, provide areaction that resists the force applied thereto through the link 29.This reaction will, of course, tend to balance the force created as aresult of the change in draft loads on the implement, and when thisreaction is sufficient to counteract the force resulting from the changein draft load there will be no longitudinal movement of the push rod 54.However, if the increased draft force produces a resultant force in saidlink that is greater than the reactive force of the torsion rod 39 therewill be a longitudinal movement of the push-rod 54 and an actuating orsensing signal will be transmitted to the actuator valve of the liftmechanism 13.

The sensing signal, generated as a result of movement of the push rod 54by the draft link 29, is used to control the power lift means 13 bycoordinated actuation of the actuator means 55. The longitudinalposition or displacement of the push-rod 54 relative to the connectingarms 49, 49 and the actuator means may be altered or adjusted onoccasion to accommodate for wear, increased sensitivity, inaccuracies ofmanufacture or the like, as desired, with a minimum of difficulty. Toaccomplish such adjustment the locking screw 44a is first loosened, thenthe eccentric cam screw 440 is turned clockwise or counterclockwise asappropriate to effect a rotative displacement of the insert bushing 42bwhich carries with it the interconnected bar 39, sleeve 36, arms 49, 49and the rod 54. When the appropriate degree of rotational displacementhas been effected the locking screw 44a is then clamped down tight tofixedly position the bushing 42b and the proximate end of said torsionrod. The actuator means may include a valve housing such as 56 suitablyassociated with and carried by the tractor frame lltl, either by beingfashioned as an integral component thereof or by being separatelyfashioned and positioned therewithin. Said valve housing is fashioned toprovide an interior chamber 57 therein connected for fluid communicationby Way of a conduit 58 with the ram cylinder 16 and by way of conduit 59with the suction inlet of a hydraulic pump, such as indicated at 60,while a conduit 58a connects the discharge outlet thereof with saidcylinder through conduit 58. A further conduit 61 connects said chamberwith a fluid reservoir such as indicated at 62. A piston, indicatedgenerally at 63 and having a forward portion 63F and a rearward portion63R with a rod 64 connected therebetween, is slidably positioned withinthe chamber 57.

A biasing spring 65 poistioned between the end of the piston portion 63Rand the proximate end wall 68 provides a suitable means for positioningthe piston and helping to locate the respective piston portions 63F and63R so that normally they overlie and close the openings from therespective conduits 59 and 58 and thereby prevent the entrance orrelease of fluid to or from the ram cylinder 16 as is well understood.

The piston assembly 63 has a connecting rod 69 connected thereto whichextends through the proximate end wall 68 of the housing 56 and has atransversely extending pin 70 in the outward end thereof. The sensingcontrol or push rod 54 is pivotally connected at its forward end, asindicated at 7-1, to a link 72 intermediate the ends thereof.

The upper end of link 72 may be fashioned wit-h a yoke or bifurcatedportion so as to be positionable to engage opposite end portions of thepin 70, in rod'69, while the opposite end of the link 72 is pivotallyconnected at 73 to a member 74 that is pivotally connected at itsopposite end by a pivot 75 to an arm 76 that represents an extension ofthe control handle 77 that, in turn, is suitably pivoted at 78 to aquadrant sector 79 mounted on the tractor frame 10. The pivotalconnection 78 may include any well-known friction means for resistingmovement of the control handle 77 out ofa preselected position exceptwhen manually motivated. Since such frictional means are conventionaland so well known for similar purposes, it was felt a full descriptionof the details of a specific frictional means herein was unnecessary.

In operation, the handle 77 is initially moved to the position on thequadrant corresponding to the anticipated draft load which, in thepresent instance, rotates it to the right, or clockwise as viewed inFIGURE 2, whereupon the attached member 74 tends to move link 72 butsince the control rod 54 is fixed at this time the link 72 rotatesclockwise about its fulcrum connection 71 with rod 54. As link 72rotates, the upper end thereof tends to move away from pin 70 in theconnecting rod 69 and thereby permits the spring 65 to move the piston63 to the right, whereupon the fluid conduit line 58 is placed in fluidcommunication through chamber 57 with the conduit line 61 and thereservoir 62 and fluid is released or exhausted from the ram cylinder16. With the release of fluid from said cylinder, the piston 17 thereinis urged to the right, as the result of the weight of the implement 26acting through the draft links 22, drop links 21, lift arms 20,rockshaft 15, crank arm 19 and rod 18, and the implement is therebylowered to enter the ground. As the vehicle moves forwardly theimplement penetrates further into the ground and the draft forces of thesoil increasingly react thereon. When the implement reaches the depthcorresponding to the preselected position of the hand lever 77, thedraft forces will be such as .to tend to rotate the implement clockwiseabout the pivot 24 and thereby put a compression force in the upper link29. This force, in turn, is resisted or reacted upon by the torsion rod39 and when said compression force becomes sufficient to override saidtorsion rod reaction the rod rotates sufliciently to cause arms 49, 49to displace the control rod 54 rearwardly as viewed in FIGURES l and 2.This rearward movement of rod 54 will cause the link 72 to rotatecounterclockwise about its pivotal connection 73 with the member 74 andthus move the upper end of said link rearwardly carrying with it the pin70 and rod 69. As the rod 69 moves the piston assembly 63 also moves andthe piston portions 63F and 63R are again positioned to cover theopenings to conduits 59 and 58 to prevent further displacement of fluidfrom the ram cylinder 16. The valve has now returned to neutral, and thedraft force resultant is balanced against the reaction of the torsionrod 39.

When the draft forces are increased, such as when encountering densesoil, obstructions, or the like, the implement will tend to rotateclockwise about its pivotal connections 24 so as to increase thecompression force in the upper link 29 and at the same time moving saidlink forwardly. As the link 29 is moved forwardly against the resistanceor reaction of torsion rod 39 the interconnected control rod 54 is movedrearwardly and this movement carries with it the connecting rod 69 andthe attached piston portions 63F and 63R so that the fluid supplyconduit suction line 59 is placed in communication through chamber 57(FIGURE 8) with conduit line 61 opening into the reservoir 62 and fluidunder pressure from the pump may be delivered by way of conduits 58a and58 to the cylinder 16 to raise the implement 26. As the implement israised the draft forces effective thereon are decreased and followingwhich the compression force in the upper link 29 is decreased whereuponthe torsion rod 39 will react to reposition said upper link and thecontrol rod 54 causing the latter to move forwardly away from pin 70 inrod 69 and thereby permitting the spring to move the piston portions 63Fand 63R forwardly to cover the conduit openings 59 and 58 and thusreturn the valve to a neutral position.

In the event the draft forces are decreased, there will be a tendencyfor the implement to rotate counterclockwise about its pivotalconnections 24 and thereby set up a tension force in the upper link 29and a compression force in the control rod 54. This compression force,in turn, causes the rod 54 to move forwardly away from pin in rod 69thereby permitting spring 65 to move the piston portions 63F and 63Rforwardly until conduit line 58 is placed in communication with thereservoir conduit line 61 which then permits fluid to be released fromthe cylinder 16 and the implement to be lowered. As the implement islowered deeper into the ground the draft forces effective thereon areincreased following which the direction of the forces in the upper link29 and control rod 54 are reduced or reversed and the reaction of thetorsion rod 39 then becomes effective to move the rod 54 rearwardlycarrying with it the rod 69 and piston portions 63F and 63R so as toreestablish the actuator valve 55 in a neutral condition.

In FIGURES 5-7 there is illustrated a modified form of the presentinvention wherein the force-resisting and yieldable means is associatedwith and reactive upon the lower draft links of the hitch mechanism. Inthese views, the same reference characters, as heretofore employed, areused to indicate identical parts, while the modified or new elementshave been referenced with different characters.

In this application of the invention the upper link 29 is pivotallyconnected, by suitable connecting means such as shown at 80, to abracket 81 that, in turn, is securedly mounted on the tractor frame 10.The lower links 22, 22 are respectively provided at their forward endswith spherical apertures 82R and 82L adapted to receive sphericalportions 83R and 83L journaled on pins 84R and 84L fixedly positioned inappropriate pin cranks. The outer ends of the pins 84R and 84L arethreaded to receive locking nuts such as 85 which may be locked in placeby conventional cotter keys such as shown at 86. It will be noted that aright-hand or right side (as viewed in FIGURE 7) pin crank, designated87R,

although generally similar to is not identical with a lefthand or leftside pin crank, indicated 87L, since the said crank 87R is provided withan enlarged recess at 88 to accommodiate a portion of an anchor bracket89 disposed on the right-hand side of the frame.

The rear portion of the tractor frame may be fashioned to provide spacedvertical walls 10a and 10b with an interconnecting wall portion 100therebetween. Aligned openings 90R and 90L in said walls accommodatetransversely extending and oppositely disposed bearing tubes 91R and 91Ljournaled therein by a plurality of sleeve bearings such as 92. Enlargedrecesses 93R and 93L, in wall portions 10a and 10b and disposed atopposite ends of the aligned openings 96R and 99L, accommodate the pincranks 37R and 87L, while the axially extending sleeve portions 94R and94L respectively, provided on said cranks, in turn, are receivable inthe bearing tubes 91R and 91L. An enlarged flange-like portion 95R onthe outer end of pin crank 87R carries the draft link pin 84R and aportion of said flange is receivable in the enlarged recess 93R in wallportion 10:: while a similar enlarged flange-like portion 95L on pincrank 87L carries the draft link pin ML and a portion of said latterflange is receivable in the enlarged recess 93L in wall portion 10b.

The pin crank 87L is provided with an axially splined opening 96L whilethe oppositely disposed anchor bracket 89 has a generally similaraxially splined opening 96R aligned therewith. The anchor bracket 89,which may be atfixed to the outer side of wall 10a by suitable securingmeans such as the bolts or cap screws 97, is provided with a cutoutportion 93 that is adapted to rotatably accommodate therewithin aportion of the pin crank 87R and its flange 95R, as best seen in FIGURE6. A dowel pin,

such as shown at 99 anchored in the wall portion 10a and receivable in aregistering opening in the anchor bracket 89, may be provided to furtherstabilize the mounting of said bracket on the proximate frame wall.

A torsion bar 100 having enlarged splined opposite end portions 100R andltltlL is positionably received in the mating splines of the openings96R and 96L in the respective anchor bracket 89 and pin crank 87L. Athreaded reduced section extension 101 on one end of said torsion bar isadapted to receive a Belleville washer 102 and a lock nut 103 thereon soas to aid in preventing axial displacement of said torsion rod. Sincethe axial opening through the extension sleeve 94R is smaller than thediameter of the splined end portion 100R of the torsion rod 104] it willbe appreciated that said rod cannot normally be axially displaced to theleft through said opening, and with the nut 103 and washer 102 in placeit cannot be displaced to the right. In this connection, it will beappreciated that the axial opening through extension sleeve 94L will beslightly larger than the splined end portion ltltlL of the torsion rod101} so as to facilitate easy assembly and disassembly of the mechanism.

A coupling sleeve 104 is mounted so as to subtend the adjacent innerends of the bearing tubes 91R and 91L, and said sleeve is suitablysecured to said tubes by the splines indicated at 195 thus the two saidbearing tubes are coupled together through said coupling sleeve forrotation as a unit. A snap-ring 106 disposed in an annular groove 107 inthe coupling sleeve 104 and located between the proximate ends of thebearing tubes 91R and 91L serves to center said coupling sleevecentrally of the frame portions 10a and 10b. Thrust collars 108R andltitlL may be disposed as shown between the pin crank members 87R and87L and the ends of the respective bearing tubes 91R and 91L withportions thereof also bearing against the radial inner wall surfaces ofthe respective enlarged recesses 93R and 93L. O-ring seals such as 109Rand 109L may be employed as indicated between the respective thrustcollars 198R and 108L and the interior area of the vehicle frame whichwill usually contain fluid under pressure as is well understood.

Tapered snap-rings 110R and 11tlL, which are positionable in annulargrooves in the respective frame portions 10a, 10b, may be provided toaid in retaining the thrust collars 108R and 108L against accidentalaxial displacement. Additional fluid scales, such as shown by referencenumeral 111, may be provided as indicated to prevent fluid leakagebetween the coupling sleeve 104 and the bearing tubes 91R and 91L. Theinner ends of the extension sleeves 94R and 94L are coupled to therespective bearing tubes 91R and 91L by means of the splinesrespectively indicated at 112R and 112L. A snap-ring 113 disposed in anannular groove in the torsion rod end portion 100R and abutting anenlarged end portion of the opening 96R may be used to affix the rod 100against axial displacement thereof in one direction relative to theanchor bracket 89.

Referring to FIGURE 6, it will be seen that a crank member 114,indicated partly in broken and partly in full lines, is aflixed, by anysuitable or well known means such as welding, brazing, splining or thelike, to and extends forwardly and upwardly from the bearing tube 91Rand as thus disposed is constrained for rotation therewith.

The upper end of the crank 114i is pivotally connected at 115 to a lever116, pivotally mounted at 117 to a support 117a aflixed to the frame 10,and the opposite end of said lever is pivotally connected at 118 to thecontrol rod member 54. The pivot 115, preferably, operates in anoversized opening in the lever 116 to provide a yieldable, sloppy orloose joint type of connection or, if desired. may be generally similarto the slot-like or irregular shaped opening shown at in FIG. 4 withoutdeviating from any of the inventive concepts hereof. The opposite orforward end of said control rod is pivotally connected, as previouslynoted, at 71 to the link 72 which, in turn, operatively connects withthe valve actuating and control mechanism heretofore described indetail.

The operation of the form of the invention shown in FIGURES 5-7 issubstantially identical to the form previously described and illustratedin FIGURES 1-4, in that the forces produced in the draft links by draftloads are resisted or reacted against by the torsional stressingreaction of a torsion bar and when such forces exceed predeterminedamounts signals are transmitted to valve actuating mechanism operativefor raising or lowering the power lift means according to the demandsimposed upon the attached implement.

Since any increase in draft loads in this instance is registered throughthe lower links and tends to rotate the torsional members clockwise, ascontrasted with the first described form of the invention where suchincrease was registered by a compression force in the upper link whichurged counterclockwise rotation, it is necessary to couple the crank arm114 to a reversing link or lever 116 so that the direction of motion ofthe control rod 54 will be the same regardless of whether draft loadsare sensed by the upper or lower links of the hitch mechanism.

In operation, the draft loads on the implement as a result of soilreaction thereon normally tends to rotate the implement clockwise aboutthe pivots 24, but, since the upper part of the rigid mast 27 ispivotally connected to the upper link 29 which resists such rotation,the lower draft links will, instead, then be subjected to a tensionforce which tends to urge them rearwardly. When this occurs the links22, 22 being connected to the pin cranks 87R and 87L will urge rotationof said cranks in a clock wise direction, as viewed in FIGURE 6, andthis movement will be carried by the sleeve members 94R, 94L, thebearing tubes 91R, 91L and the interconnected coupling sleeve 104 to thetorsion rod which, being connected by splining at the end portion IMLthereof to the pin crank 87L, will rotate therewith. Since the oppositeend of said torsion rod is connected by splining at 100R to the anchorbracket 89, in turn, fixedly secured to the tractor frame, the rod willnot be free to rotate but will, instead,

set up a yieldable torsional reaction opposing such rotation. Anyrotation of the bearing tube 91R is, of course, accompanied by acorresponding rotation of the attached crank member 114 which thereuponattendant such movement transmits a sensing signal through the controlrod 54 to actuate the valve unit 55 and subsequently operate the liftcylinder and hitch mechanism.

It will be appreciated, of course, as previously noted, that a decreasein draft loads will permit reversal of direction of the resultant forcesin the control rod member with an attendant movement of the valve in adirection such as to effect a release of fluid from the lift cylinderand a lowering of the attached implement.

It will be readily apparent that the proposed invention provides a verysimple, highly effective and inexpensive to fabricate force-resistingand yieldable means for balancing out draft loads in a hitch mechanism.It will also be recognized that the proposed invention is readilyapplicable to conventional hitch mechanisms without necessitatingsubstantial redesign or reconstruction, and additionally, that suchdevice is positive in action and can be 'made as sensitive as desired.

The foregoing and other desirable features not specifically enumeratedherein will undoubtedly occur to those versed in the art, as willnumerous modifications and alterations in the preferred forms of theinvention disclosed, all of which may be achieved without departing fromthe spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. In a tractor having power lift means for raising and lowering avehicle-borne implement, and actuator means for controlling theoperation of said lift means, the combination, comprising: tubular meanssupportably mounted by the tractor for rotative movement and disposedtransversely thereof; an elongated bar positioned within said tubularmeans and having one end thereof anchored against rotation relative tothe tractor and the other end constrained for rotative movement withsaid tubular means and being resilienly yieldable upon torsionalstressing in any ,j'direction of rotation; implement-connecting draftmeans having a pair of elements spaced apart lengthwise of andrespectively connected to end portions of said tubular means fortorsionally stressing the attached bar in response to implement draftloads; crank arm means extending from a midportion of and constrainedfor rotation with said tubular means; and sensing means interconnectedbetween said crank arm means and the actuator means and operative fortransmitting movements of said tubular means to the actuator means foreffecting operation of the power lift means.

2. The structure defined in claim 1 and further characterized in thatthe tubular means includes crank arms disposed one at each end of saidtubular means and are connected thereto for movement therewith, andfurther in that said pair of draft elements are connected to said crankarms for rotative movement thereof and consequent torsional stressing ofthe said elongated rod in response to implement draft loads.

3. In a tractor having power lift means for raising and lowering avehicle-borne implement, and actuator means for controlling theoperation of said lift means, the combination, comprisingz'tubular meanssupportably mounted by the tractor for rotative movement and disposedtransversely thereof; a pair of crank arms connected one each to andextending from an end of said tubular means; an elongated bar positionedwithin said tubular means and having one end thereof extending into andconstrained for rotative movement with one of said crank arms;detachable means supportably affixing the opposite end of said bar tothe tractor for preventing movement of said opposite end of said barrelative to the tractor, and having said bar resiliently yieldable upontorsional stressing in either a clockwise or counterclockwise directionof rotation; implement-connecting draft means having a pair of draftlinks spaced apart lengthwise of said tubular means and respectivelyconnected to said crank arms for rotative movement thereof andconsequent torsional stressing of said elongated bar in response toimplement draft loads; crank arm means connected to a midportion of andconstrained for rotative with said tubular means and extending therefromangularly displaced relative to said pair of crank arms; and sensingmeans interconnected between said crank arms means and the actuatormeans and operative for transmitting movements of said tubular means tothe actuator means for effecting operation of the power lift means.

4. In a tractor having a frame casing portion fashioned to providelaterally spaced opposite side Walls and supportably carrying a powerlift means for raising and lowering a vehicle-borne implement, andactuator means for controlling the operation of said lift means, thecombination, comprising: tubular means transversely disposed relative tothe frame casing and having the casing side walls provided with alignedapertures for rotatably accommodating opposite end portions of thetubular means therein; a pair of crank arms connected one each to andextending from an end of said tubular means; an elongated bar positionedwithin said tubular means and having one end thereof extending into andconstrained for rotative move- .ment with one of said crank arms;detachable means supportably aflixing the opposite end of said bar tothe tractor casing portion and arranged to prevent movement of saidopposite end of said bar relative to the tractor, and having said barresiliently yieldable upon torsional stressing in either a clockwise orcounterclockwise direction of rotation; implement-connecting draft meanshaving a pair of draft links spaced apart lengthwise of said tubularmeans and respectively connected to said crank arms for rotativemovement thereof and consequent torsionsal stressing of said elongatedbar in response to implement draft loads; crank arm means connected to amidportion of and constrained for rotation with said tubular means andextending therefrom angularly displaced relative to said pair of crankarms; and sensing means interconnected between said crank arm means andthe actuator means and operative for transmitting movements of saidtubular means to the actuator means for effecting operation of the powerliftv means. 1

5. The structure defined in claim 4 and further characterized in thatsaid tubular means includes a pair of axially aligned tubular membersand an additional tubular .member concentric with and overlyingproximate end portion fashioned to provide laterally spaced oppositeside walls and supportably carrying a power lift means for raising andlowering a vehicle-borne implement, and actuator means for controllingthe operation of said lift means, the combination, comprising: tubularmeans transversely disposed relative to the frame casing and having thecasing side walls provided with aligned apertures for rotatablyaccommodating opposite end portions of the tubular means therein; fluidsealing means disposed one each between opposite end portions of saidtubular means and respective side wall apertures; said side walls beingprovided with an enlarged recess adjacent the outward end of eachaperture therein; a pair of crank arms disposed one in each of saidrecesses and connected one each to and extending from an end of saidtubular means; an elongated bar positioned within said tubular means andhaving one end thereof extending into and constrained for rotativemovement with one of said crank arms; detachable means supportablyaffixing the opposite end of said bar to the tractor casing portion andarranged to prevent movement of said opposite end of said bar relativeto the tractor, and

having said bar resiliently yieldable upon torsional stressing in eitherclockwise or counterclockwise direction of rotation;implement-connecting draft means having a pair of draft links spacedapart lengthwise of said tubular means and respectively connected tosaid crank arms for rotative movement thereof and consequent torsionalstressing of said elongated bar in response to implement draft loads;crank arm means connected to a centrally disposed portion of andconstrained for rotation with said tubular means and extending therefromangularly displaced relative to said pair of crank arms; and sensingmeans interconnected between said crank arm means and the actuator meansand operative for transmitting movements of said tubular means to theactuator means for effecting operation of the power lift means.

7. The combination with a tractor having a longitudinal frame and atransverse rear axle housing assembly portion and substantiallyhorizontal wheel mounting axle means therein, implement attaching draftmeans behind the tractor having upper and lower link means with saidlower link means including a pair of draft members spaced apart atforward ends thereof, means mounting said lower link means coaxially tothe tractor on an axis generally parallel to the axle means below thesame, means mounting said upper link means to the tractor above the axlemeans, said rear axle housing assembly portion having a pair ofcoaxially aligned openings therethrough disposed on an axis generallyparallel to the axle means at a level vertically displaced from thesame, a torsion bar assembly having an axis of operation generallyparallel to the axle means, means journally mounting said-torsion ,barassembly within said openings and having opposite end portions of saidassembly extending outwardly one portion each beyond an outer edge of arespective opening, crank means mounted on said torsion bar assembly,said torsion bar assembly serving as the axis of pivot for the crankmeans and operative to transmit implement draft loads to the tractor indraft forces oriented about said axle means, said crank means includingupper and lower arm means, draft sensing means on the tractor connectedto said upper arm means, said lower arm means including crank membersmounted one each on said torsion bar assembly end portions and havingsaid pair of draft members connected one each to a respective crankmember.

8. The invention according'to claim 7 and further characterized in thatsaid outwardly extending opposite end portions of said torsion barassembly are fashioned to include separate tubular means and havingadditional tubular means interconnecting said separate means, andfurther in that the upper arm means of said crank means is mounted onsaid additional tubular means and constrained for rotation therewith.

9. The combination with a tractor having a longitudinal frame and atransverse rear axle housing assembly portion and substantiallyhorizontal wheel mounting axle means therein, implement attaching draftmeans behind the tractor having upper and lower link means with saidlower link means including a pair of draft members spaced apart atforward ends thereof, means mounting said lower link means coaxially tothe tractor on an axis generally parallel to the axle means below thesame, means mounting said upper link means to the tractor above the axlemeans, said rear axle housing assembly portion having a pair ofcoaxially aligned openings therethrough disposed on an axis generallyparallel to the axle means at a level vertically displaced from thesame, a torsion bar assembly mounted within said openings and having anaxis of operation generally parallel to the axle means, said torsion barassembly having inner and outer telescoped elements, said outer elementbeing generally tubular in form and said inner element in the form of arod, said tube and rod elements interconnected at one of theircorresponding ends, a pair of bearing means sleeved over said tube andspaced longitudinally thereof and disposed in tight fit relationship onein each of said openings, the outer tubular element of said torsion barassembly having opposite end portions extending outwardly one portioneach beyond an outer edge of a respective opening, means connectinganother end of said rod to said housing assembly portion in an areaspaced longitudinally of the area of location of said bearing means,crank means mounted on said outer tubular element, said outer tubularelement serving as the axis of pivot for the crank means and operativeto transmit implement draft loads to the tractor in draft forcesoriented about said axle means, said crank means including upper andlower arm means, draft sensing means on the tractor connected to saidupper arm means, said upper arm means of said crank means being mountedon said outer tubular element in an area intermediate said pair ofopenings, said lower arm means including 'a pair of crank membersmounted one each on said outer element end portions and having said pairof draft members connected one each to a respective crank member.

10. In a tractor, the combination of a body structure having a pair oftransversely spaced hitch supporting members; a torsion bar extendingaxially through aligned apertures of said members and non-rotatablyconnected at one of its ends with one of said members; a tubular memberrotatably mounted at its axially opposite ends, respectively, in saidapertures of said members in surrounding relation to said torsion barand having an end portion adjacent to the other of said membersnonrotatably connected with the other end of said torsion bar; a pair ofmounting arms for a pair of draft links nonrotatably secured to saidtubular member{ and an actuating element for a power lift controlmechanism connected with said tubular member so as to be swung back andforth about the axis of the latter by back and forth rotation of saidtubular member in said members.

lll. The combination with a tractor having a longitudinal frame and atransverse rear axle housing assembly portion and substantiallyhorizontal wheel mounting axle means therein, implement-attaching draftmeans behind the tractor housing having upper and lower link means,means mounting said lower link means coaxially to the tractor on an axisgenerally parallel to the axle means below the same, means mounting saidupper link means to the tractor above the axle means, said rear axlehousing assembly portion having a pair of coaxially aligned openingsdisposed on an axis generally parallel to the axle means at a levelvertically displaced from the same, a torsion bar assembly having anaxis of operation generally parallel to the axle means at a level belowthe same, means journally mounting said torsion bar assembly within saidopenings, crank means mounted on said torsion bar assembly, said torsionbar assembly serving as the axis of pivot for the crank means andoperative to transmit implement draft loads to the tractor in draftforces oriented about said axle means, draft sensing means on thetractor connected to said crank means, and having said lower one of saidimplementattaching draft means connected to said crank means.

12. The combination with a tractor having a longitudinal frame and atransverse rear axle housing assembly portion and substantiallyhorizontal wheel mounting axle means therein, implement-attaching draftmeans behind the tractor housing having upper and lower link means,means mounting said lower link means coaxially to the tractor on an axisgenerally parallel to the axle means below the same, means mounting saidupper link means to the tractor above the axle means, said rear axlehousing assembly portion having a pair of coaxially aligned openingsdisposed on an axis generally parallel to the axle means at a levelvertically displaced from the same, a torsion bar assembly having anaxis of operation generally parallel to the axle means, means journallymounting said torsion bar assembly within said openings, crank meansmounted on said 13 14 torsion bar assembly, said torsion bar assemblyserving as References Cited by the Examiner the axis of pivot for thecrank means and operative to UNITED STATES PATENTS transmit implementdraft loads to the tractor in draft 2,705,154 3/1955 Torre 267 57 Xforces oriented about said axle means, draft sensing means 2,950,1038/1960 Ruf on the tractor, and said crank means including upper and 5 3022 830 2/1962 H 172 7 lower arm means with said upper arm means beingcon- FOREIGN PATENTS nected to said draft sensing means and said lowerarm 606 867 7/1960 It 1 means being connected to the lower link means ofsaid a implement-attaching draft means. 10 ABRAHAM G. STONE, PrimaryExaminer.

1. IN A TRACTOR HAVING POWER LIFT MEANS FOR RAISING AND LOWERING AVEHICLE-BORNE IMPLEMENT, AND ACTUATOR MEANS FOR CONTROLLING THEOPERATION OF SAID LIFT MEANS, THE COMBINATION, COMPRISING: TUBULAR MEANSSUPPORTABLY MOUNTED BY THE TRACTOR FOR ROTATIVE MOVEMENT AND DISPOSEDTRANSVERSELY THEREOF; AN ELONGATED BAR POSITIONED WITHIN SAID TUBULARMEANS AND HAVING ONE END THEREOF ANCHORED AGAINST ROTATION RELATIVE TOTHE TRACTOR AND THE OTHER END CONSTRAINED FOR ROTATIVE MOVEMENT WITHSAID TUBULAR MEANS AND BEING RESILIENTLY YIELDABLE UPON TORSIONALSTRESSING IN ANY DIRECTION OF ROTATION; IMPLEMENT-CONNECTING DRAFT MEANSHAVING A PAIR OF ELEMENTS SPACED APART LENGTHWISE OF AND RESPECTIVELYCONNECTED TO END PORTIONS OF SAID TUBULAR MEANS FOR TORSIONALLYSTRESSING THE ATTACHED BAR IN RESPONSE TO IMPLEMENT DRAFT LOADS; CRANKARM MEANS EXTENDING FROM A MIDPORTION OF AND CONSTRAINED FOR ROTATIONWITH SAID TUBULAR MEANS; AND SENSING MEANS INTERCONNECTED BETWEEN SAIDCRANK ARM MEANS AND THE ACTUATOR MEANS AND OPERATIVE FOR TRANSMITTINGMOVEMENTS OF SAID TUBULAR MEANS TO THE ACTUATOR MEANS FOR EFFECTINGOPERATION OF THE POWER LIFT MEANS.